At least 200 people have been killed in a massive earthquake in Japan that also triggered a devastating tsunami. The quake - the most powerful to hit Japan in at least 100 years - caused massive damage and many people are missing and feared dead.

Video images from coastal areas struck by the tsunami showed widespread inundation as mud waves carried tons of debris over farmland in Sendai, the capital of Miyagi prefecture. Large-scale damage could be seen in various locations along the coast. In Chiba prefecture, a massive oil refinery fire has broken out.

Video clip: Japan earthquake

In Tokyo, hundreds of kilometers away, buildings shook violently and items fell from shelves. The roof of at least one building collapsed.

Piere Manea, a student in Tokyo, ran out of his university dormitory when the quake struck.

"We were in the university building and it was quite strong, so after a few seconds we decided to go down. We were on the fifth floor and it was really strong," Manea said.

Kate Woodsome's Q&A with USGS Geophysicist Randy Baldwin:

The powerful quake struck Friday about 125 kilometers off Japan's eastern coast, at a depth of 10 kilometers.

Addressing the nation, Japanese Prime Minister Naoto Kan said the government would do anything it can to minimize the effects of the disaster.

Kan says he has created an office to deal with the disaster and maintain safety. He says the government will work to reduce the amount of damage to the smallest amount possible.

More than four million homes remain without power. Nuclear power stations, of which there are three in the region, either continued operating or were automatically shut down. Tokyo Electric Power said no radiation leaks were immediately detected.

The quake disrupted transportation across a large part of Japan. Trains automatically stopped, expressways were closed and flights halted.

Japan Rail has suspended all train services in the Tokyo region for the remainder of Friday. Hundreds of thousands of people are stranded in the city or have faced a long walk home.